Field of the Invention
The invention describes a method of checking the functionality of a processor. The processor thereby receives a data word from a second processor, the data word is modified by the first processor, and the second processor monitors whether the data word is modified by the first processor up to a specified instant.
Particularly in motor vehicles, safety-related functions are increasingly controlled by processors. The processors must therefore be checked for correct operation. Correct operation of the processor includes timely and punctual processing of the specified functions. Such functionality may be checked with a delay time monitor, for example.
German published non-prosecuted patent application DE 41 14 999 A1 describes a system for controlling a motor vehicle. A first processor determines the control data for a motor vehicle, and a second processor monitors the first processor. The first processor and the second processor are each connected to an independent time base. The second processor supplies the first processor with first data, which the first processor uses to calculate, on the basis of computation instructions, a result which it returns to the second processor. The second processor checks whether the data passed back by the first processor have been returned correctly and punctually.